I got my AC2 today! Woooooo eh?
My speed test maxed at 10mb both directions. My ISP’s built in 5ghz gets 60 down and 10 up.
What gives? All default settings, nothing changed except the wifi names so i knew what was 2.4 and what was 5.8
This is know issue.
You can check a similar post on this forum http://forum.mikrotik.com/t/hap-ac-2-problems-extremely-poor-performance-found-in-2-4g-and-5g-wifi/118063/1
The Mikrotik engineers are working on a fix http://forum.mikrotik.com/t/v6-40-7-bugfix-is-released/118159/30
Known issues with ARM devices. Use the latest RC software release and update firmware.
Help is coming, but this will be on the RC release channel only as I understand it.
Welcome to the club 
Topic locked as redundant. Please continue in referenced topic instead.